I ask this question from a European country; consider your answers this way.
Some people are unable to differentiate serious talking, jokes, and irony or sarcasm. Specifically for the latter, as it's a very thin line between seriousness and joking (and the meaning of sarcasm and irony is also not always well-defined), how should I be aware of someone using irony and/or sarcasm?
Usually, people can notice it "in their guts", as if it was some sort of reflex. If I'm not wrong, then how can I "adapt" this reflex? If I'm wrong, then what should I consider?